Study of Si(111) surfaces by optical second-harmonic generation: Reconstruction and surface phase transformation

Optical second-harmonic generation has been applied to the study of clean Si(111) 2×1 and 7×7 surfaces. By an analysis of polarization dependences of the two reconstructions, the symmetry properties of the surfaces have been determined. The 2×1 to 7×7 surface phase transformation during thermal annealing has also been monitored in real time by the second-harmonic technique. © 1985 The American Physical Society.